1. Field of the Invention
The present invention relates to wrappers for smokable articles such as cigarettes. Such articles are conventionally made by wrapping tabbacco in paper which is made from flax, or other cellulosic fibers, and calcium carbonate filler. Papers of this composition are standard in today's cigarettes. The burning cigarette releases smoke which may be classified as sidestream when it emanantes from the lit end of the cigarette or mainstream when it is drawn through the tobacco column to the smoker. The present invention is directed to an improved method and wrapper that materially reduce the quantity of the sidestream smoke.
2. Description of the Prior Art
Various attempts have been made to reduce the level of sidestream smoke. However, none has been successful to the point of significant commercial exploitation. For example, U.S. Pat. No. 4,225,636 to Cline et al issued 30 September 1980 is directed to the use of high porosity carbon coated cigarette papers disclosed to provide substantial reductions in both mainstream and sidestream smoke. U.S. Pat. No. 3,744,496 to McCarty et al issued 10 July 1973 is also directed to a carbon filled wrapper which is preferably treated with compounds such as alkali metal hydroxides, bicarbonates and carbonates. It also has been recognized that some smoking articles wrapped in tobacco leaf release lower amounts of sidestream smoke, but such wrappers are not practical for use on cigarettes. These products, as well as those resulting from other attempts at sidestream reduction, have suffered either from excessive cost or adverse effects relating to mainstream particulate deliveries, draw, taste, or other factors such as burn rate. Therefore, none of these has represented a practical solution for decreasing sidestream smoke from cigarettes.
Many of the compounds useful in accordance with the invention described herein have been known as additives to wrappers for smokable articles primarily as burn enhancers. For example, U.S. Pat. No. 4,231,377 to Cline et al issued 4 November 1980 describes a wrapper containing at least 15% by weight magnesium oxide or its hydrate plus at least 0.5% by weight of a chemical adjuvant which may include alkali metal acetates, carbonates, citrates, nitrates, or tartrates. Examples are included wherein a maximum of 3.5% of the chemical adjuvant is applied. Other references to the use of such compositions include U.S. Pat. No. 3,861,401 to Briskin et al issued 21 January 1975; U.S. Pat. No. 3,797,504 to Hughes et al issued 19 March 1974 and U.S. Pat. No. 3,667,479 to Sanford et al issued 6 June 1972, each of which describes improvements in burn properties.
Notwithstanding such descriptions, the problem of sidestream smoke remains, and the present invention provides a practical and effective cellulosic wrapper for smokable articles that reduces sidestream smoke while avoiding significant deterioration of other desirable properties.